Existing regulations specify a total amount of exposure to RF energy, above a threshold power density, that a user of a wireless terminal can be exposed to within a predetermined interval of time (e.g., averaged over one half hour).
One technique to determine the user's exposure would be to monitor the radiated power within the user's terminal and average over time the radiated power that exceeds the threshold. If the threshold level is exceeded within the specified interval of time, the user terminal could be rendered inoperable, thereby removing the user from the transmitted RF energy.
However, this approach could result in user terminals being modified or manufactured so as to defeat this function. Although the convenience to the user of always having the terminal available for use could be assured, the user may be exposed to potentially harmful levels of RF energy.
Furthermore, a user terminal that is manufactured to operate with a specified allowable average power density could be rendered obsolete if the threshold level is later changed. As such, providing this function in the user terminal has a number of drawbacks.